A static IP address is one that does not change. Normally, you only have one of those if you're connected to a LAN, or you have a major operation on the Internet, where you need a DNS name to map to an IP address.
A Dynamic IP address is usually given to those of us who don't really care or need to have a static IP address. For instance, with a dial-up connection, you're alotted an IP address that you only keep for the time that you're connected. Then, when you disconnect, someone else might be given that IP address, since you're not using it.
A Static IP is one that you get from the ISP and which is permanent.The IP that keeps changing is known as Dynamic IP.You can easily find whether you have a Static or Dynamic one either by contacting your ISP or by checking the external IP in sites like Ip-details.com if you reset the modem and again check in the same site;if it is a dynamic one you will have different IP's and if you own a Static IP the IP will not change even after you reset the modem.